Davit device

ABSTRACT

A davit device ( 20 ) is arranged suspended over an associated boat ( 123 ) onboard a ship ( 25 ) or similar vessel. Horizontally, telescopically displaceable davit arms ( 121, 121 ) can move the boat ( 123 ) from a parking position to a launching position, and vice versa, while a hoisting device ( 122 ) can move the boat ( 23, 123 ) vertically. In that the hoisting device ( 122 ) is secure to the radially innermost, axially extendable telescope part ( 121   a   , 121   a ) of the davit arms ( 121,121 ), the vertical and horizontal movements can be carried out independently, in a controlled way.

The present invention relates to a davit device, which is arrangedsuspended over an associated boat on board a ship or vessel, comprisingone or a couple of horizontally telescopically displaceable davit arm(s)for movement of the boat from a parking position to a launch position,and vice versa, including hoisting devices for lowering and hoisting ofthe boat.

According to known methods, many practical advantages are gained byarranging the davit device suspended at a height above the deck of theship and the associated boat, i.e. suspended over and in its entirety ata height above the boat. Thereby, the davit device can be placed on theship without requiring much space.

In particular, it is an advantage to arrange the davit device at aheight substantially above the deck of the ship, so that it is possibleto secure a relatively free deck space under the davit device. Thereby,deck space is freed. When the boat takes up its parking position, onecan, for example, ensure relatively free passage for people at a levelunder the davit device, or under the boat itself, respectively, in thosecases where this will be relevant.

However, with known embodiments of a davit device of the above mentionedtype, it is common to arrange the hoisting devices, i.e. the winchitself and associated hoisting equipment, stationary on the deck of theship or stationary at a certain height above the deck of the ship, suchthat the hoisting devices are easily accessible for manual operationfrom the deck of the ship.

However, such a manual, easily operated arrangement takes upconsiderable space on the deck area and, in addition, complicates thehandling of the boat when it is launched or taken in. In such anarrangement, the hoisting devices must generally be guided in synchronywith the telescopic movements of the davit device. To be more precise,the pulling in and taking out of the hoisting line is guided in stepwith the telescopic movements of the davit device during launching andhoisting in of the boat, respectively, i.e. during horizontal movementof the boat with respect to the ship. In other words, during thetelescopic pushing out and pushing in, respectively, of the davitarm(s), one must provide an equivalent lengthwise compensation in thehoisting line itself and then with a full weight load from the boat inthe hoisting line.

One aims with the present invention, to avoid the above mentionedcomplications.

The davit device according to the invention is characterised in that thehoisting devices are securely fastened to the radially, innermost,axially extendable telescope part of the davit arm/davit arms, by way ofone, or a set of, carrier arms which can be moved in a groove in astationary secured telescope part.

Thus, it is possible to simplify the control of the different movements,which the boat will be subjected to, by moving the hoisting devicetogether with the innermost, axially extendable telescope part of thedavit arm/davit arms. Thereby, one can, in a safe and controlled way,displace both the boat and the hoisting device horizontally—by way ofone simple telescopic davit arm, by way of a pair of telescopic davitarms, respectively, and thus hoist and lower the boat with regard to theship with controlled movements of the hoisting line, independent of themovements of the davit arm/arms.

Further features will become apparent from the subsequent descriptionwith reference to the enclosed drawings, which show two relevantexamples of embodiments of the use of the davit device in connectionwith a working boat an a lifeboat respectively, in which:

FIG. 1 shows a single davit arm according to the invention in firstembodiment in connection with a single wire hoisting device for handlingof a working boat, which is shown in side view, with unbroken lines in alaunching position and shown with broken lines in a parking position.

FIG. 2 shows the davit arm viewed from below and with certain parts hownin horizontal section.

FIG. 3 show the davit device in section, shown partly in side view andpartly in vertical section.

FIG. 4 shows a cross section of the davit device.

FIGS. 5 and 6 show the davit device separately in the parking positionand launching position, respectively, of the boat.

FIG. 7 shows, in side view, a davit device according to the invention inanother embodiment in connection with a double-wire hoisting device forhandling of a lifeboat, which is shown in a parking position.

FIG. 8 shows, in side view, the same as is shown in FIG. 7, but shown inlaunching position.

FIG. 9 shows, in an end view, the same as is shown in FIG. 7, but withcertain parts shown in section.

FIG. 10 shows, partly in plane view and partly in section, the same asis shown in FIG. 7, including the lifeboat.

FIG. 11 shows the same as is shown in FIG. 10, without the lifeboat.

FIGS. 12 And 13 show, in perspective and partly in section, a section ofthe ship with associated davit device in parking and launching position,respectively.

According to a first embodiment example, as is shown in FIGS. 1-6, adavit device 20 is shown with one single davit arm 21. A single-wirehoisting device 22 is used for handling of, i.e. for hoisting andlowering, respectively, a boat 23 of the type working boat or so calledMOB-boat (man-overboard-boat).

The davit device 20 according to the invention is shown in form of acontinuous unit of davit arm 21 and hoisting device 22. The continuousunit is shown in a way that is not space demanding, in a suspendedposition underneath an overhanging deck or a similar roof-formingcarrier construction 24 onboard a ship 25.

The davit arm 21 is comprised of a radially innermost telescope part 21a, which can be moved axially with respect to a radially outermosttelescope part 21 b. The telescope part 21 b is shown secured directlyto the overhanging deck or similar roof-forming carrier construction 24.

The davit arm 21 with associated hoisting device 22 is shown in thedrawings suspended at a substantial height over the ship's 25 deck 26,which lies below, so that the space under the davit device 20 is easierto access for free passage.

The hoisting device 22 is secured directly to the radially innermosttelescope part 21 a by way of a couple of carrier arms 27, 28 (see FIGS.1 and 3), which run through the downward opening slot 29 (see FIGS. 4-6)in the radially outermost telescope part 21 b.

The hoisting device 22 is comprised of a hydraulically driven hoistingwinch 30 with associated single running hoisting wire 31. The hoistingwire 31 (see FIGS. 5 and 6) runs from the hoisting winch 30 over a firstpulley 32 to a second pulley 33 by way of an intermediate pulley 34 in atension-type shock-absorbing device 35. At 36 (see FIGS. 5 and 6) asupport roll is shown to support the hoisting wire 31 in its positionwith respect to the pulleys 32, 33.

In FIG. 1, the boat 23 is shown with dotted lines in parking position,resting on the deck 26 of the ship 25 by way of a horizontalkeel-support 37 and a couple of vertical side-supports 38 on the sidefacing the ship. The side-supports 38 are equipped on top with lockingbodies 39 which are pivotable, for locking of the boat in place in theparking position.

In FIG. 1 the boat 23 is shown with full lines in a launching position,hanging in the hoisting-wire 31 immediately outside the outer side 25 aof the ship 25, made ready for boarding from the deck 26 of the ship.

With dotted lines in FIG. 1, a couple of slides 40 are shown, which inthe boat's parking position are placed on the underside 23 of the boatand which in the launching position of the boat 25 (shown by the fulllines) are shown rotated to a vertical position aligned with the outerside of the ship 25. Thereby, in an itself known way, the boat 23 can,during launching and hoisting respectively, be guided in a glidingfacility against the slides and outer side of the ship 25, respectively,according to need. The slides 40 can rotate around a horizontal axis 41a at the outer side 25 a of the ship 25, i.e. along the edge of the deck26 of the ship 25, with the aid of individually associated correspondinghydraulic cylinders 42.

Between a bulkhead 25 b of a ship and the side-supports 38, a passage 25c is shown for a person P at a level essentially underneath the davitarm 21 and the hoisting device 22.

At the edge of the deck 26 of the ship 25, a service-space forlaunching/pulling in of the boat is shown. Also shown is a manoeuvrevalve 43 with associated hydraulic engine 44, pressure-accumulator 45and connecting lines 46. A protective tube 47 with internal lines 47a-47 d runs from the service space by way of the deck 26 and thebulkhead 25 b of the ship to the overhanging deck 24 and further on byway of the flexible lines 47 a-47 d to the internal telescope part 21 aof the davit arm 21. From the telescope part 21 a, the lines 47 a-47 dbranch off to the hoisting winch 30 and to a pressure cylinder 21 crespectively (not shown in detail) to the tension-type shock-absorbingdevice 35. A piston rod 21 d, which has one end fastened to a piston(not shown) in the pressure cylinder 21 c, has its opposite end fixed tothe bulkhead 25 b of the ship (see FIG. 6) in a fitting 21 e.

With the help of the manoeuvre valve 43, one can in succession and eachin turn:

hoist the boat 23 from the keel-support 37 by way of the hoisting winch30,

displace the boat 23 and the hoisting device 22 horizontally by way ofthe pressure cylinder 21 c of the davit arm 21 from a position over thedeck 26 of the ship 25 to a position outside the outer side 25 a of theship, and thereafter

lower the boat 23, for example to the position which is shown by thefull lines in FIG. 1.

The above-mentioned movements can be carried out in turn andindividually, i.e. in a controlled way with mutually independentmovements. The vertical movements of the boat are carried out from thehoisting winch 39 in the movable telescope part 21 a of the davit arm21, while the horizontal movements of the boat are carried out bypushing out and pushing in, respectively, of the movable telescope part21 a of the davit arm 21 with respect to the stationary telescope part21 b of the davit arm 21, i.e. by simultaneous horizontal displacementof the boat 23 and the hoisting device 22.

After boarding the boat 23, the manoeuvre.valve 43 can, with the help ofin itself know components, be remote controlled from the boat 23 forfurther lowering of the boat to the sea surface. In the same way, theboat 23 can, in a subsequent phase after use of the boat, after hookinga securing hook to the hoisting line 31, be hoisted onboard again withthe equivalent remote control of the manoeuvre valve 43.

The davit arm 21 is shown in FIGS. 1 and 5 in an axially fully extendedcondition and in FIGS. 3 and 6, the davit arm 21 is shown in fullypulled in, i.e. retracted position.

In FIGS. 5 and 6, flexible lines are shown, i.e. pressure-oil lines 47a-47 d in the opposite outer positions of the davit arm 21. Thepressure-oil lines 47 a-47 d are supported on a rail 48, which arecarried, by way of the vertical carrier-arms 48 a-48 c, in the outermosttelescope part 21 b of the davit arm 21.

The external telescope part 21 b is, as it clearly can be seen in FIGS.5 and 6, fitted with a series of transverse bracing plates 49, which inturn are rigidly connected to an overhanging deck or roof-formingconstruction 24.

According to another embodiment example, as shown in FIGS. 7-13, a davitdevice 120 is shown with a couple of mutually parallel davit arms 121,121, which together carry and are mutually reinforced by way of anintermediate cross bar 121 d. The cross bar 121 d is used as a carrierbody for a hoisting device 122 for handling of a boat 123 of the typelifeboat. In addition, the cross bar 121 d is used as carrier body forthe power unit of the hoisting device 122, etc.

The lifeboat 123 is carried, in the shown embodiment example, by theopposite ends in a double-wire hoisting line, i.e. with the aid of twoseparate wires 131, 131, which are handled by way of their own drum on acommon winch 130.

Each of the davit arms 121 is comprised of a radially innermosttelescope part 121 a, which can be displaced axially with respect to aradially outermost telescope part 121 b.

The radially outermost, i.e. the stationary, secured telescope part 121b, is (in a corresponding way as the stationary, secured telescope part21 b in the first embodiment example) secured to an overhangingroof-forming deck or similar carrier construction 24 onboard a ship 25at a level considerably over the below lying deck 26 of the ship 25,which is shown.

In this embodiment example, the lifeboat 123 is shown in a parkingposition raised up from the deck 26, i.e. shown at a level which permitsfree passage for a person P on the underside of the lifeboat 123 itself.In this case, a hoisting device 122 and a corresponding power unit,including a manoeuvre valve 143 with associated hydraulic engine 144with pressure-oil pump, pressure-accumulator 145 is and connecting lines146, are secured directly to the cross bar 121 d between the twomutually parallel davit arms 121 and the innermost telescope part 121 a,respectively. Thereby, a substantial area of the deck 26 of the ship 25under the lifeboat 123 is freed.

One aim is to achieve remote control of the manoeuvre valve from anyposition on the deck 26 of the ship 25 by means of in itself knownequipment. This results in the whole deck area underneath and nearby thelifeboat being made available for free passage, as is illustrated by aperson P in FIGS. 7 and 9.

In FIG. 8, the lifeboat 123 is shown after it is displaced sidewaysoutwards from a parking position, as is shown in FIGS. 7 and 9, to alaunching position outside the outer side 25 b of the ship 25 by way ofthe davit arms 121, and thereafter, by way of the hoisting lines 131, islowered down to boarding position, approximately aligned with the deck26 of the ship 25.

The vertical and horizontal movements, which the lifeboat is subjectedto, are carried out in a way corresponding to that of the firstembodiment example.

The davit arms 121, 121, which can be displaced telescopically, areshown in an axially retracted condition and axially extended conditionin FIG. 12 and FIG. 13, respectively.

What is claimed is:
 1. A davit device (20), which is arranged suspendedover an associated boat (23, 123) onboard a ship (25) or similar vessel,incorporating horizontally telescopically displaceable davit arm(s) (21;121,121) for moving of the boat (23, 123) from a parking position to alaunching position, and vice versa, and hoisting devices (22, 122) forlowering and hoisting of the boat (23, 123), characterised in that thehoisting devices (22, 122) are securely fastened to the radiallyinnermost axially displaceable telescope part (21 a; 121 a, 121 a) ofthe davit arm/davit arms (21; 121, 121), by way of one or a set ofcarrier arms (27, 28), which are displaceable in a groove in astationary, secured telescope part (21 b; 121 b, 121 b).
 2. The davitdevice in accordance with claim 1, cnaracterised in that the power unit(144, 145) of the hoisting device (122) and the manoeuvre valve (143) isarranged in a suspended position over the associated boat (123).
 3. Adavit device in accordance with claim 2, in which the davit device (120)includes two mutually parallel, telescopically displaceable davit arms(121) and an intermediate cross bar (121 d) with a associated hoistingdevice (122), characterised in that the cross bar (121 d) in addition tothe carrier device for the hoisting device (122) form a carrier devicefor the power unit (144, 145) and the manoeuvre valve (143) withassociated fittings.